Cellular communications systems for providing communications services to mobile terminals are known and widely used. The cellular structure of such systems allows a mobile terminal connected to one cell (the so-called serving cell) of the system to switch to a neighbouring cell, e.g. when a neighbouring cell becomes more suitable to be connected to due to a movement of the mobile terminal. This process of switching cells is normally referred to as handover (HO). To this end, a mobile terminal connected to a network node makes on a regular basis measurements on the serving as well as detected neighbouring cells in order to find the most suitable cell to be connected to. In case another cell than the currently serving cell becomes strong, a HO is triggered and the terminal informs the cellular network (NW) to change serving cell. The NW then makes necessary internal signalling and sets up the HO and then the terminal is informed and the HO is executed.
In certain situations, a given change in the radio environment may trigger multiple events. For example when the signal strength of the serving cell drops and the signal cell of a neighbouring cell increases, this may trigger multiple handover events, e.g. an event of a first event type indicating that the signal strength of the serving cell has dropped below a predetermined threshold, an event of a second event type indicating that the signal strength of the neighbouring cell has increased above a predetermined threshold, and an event of a third type indicating that the signal strength of the neighbouring cell has exceeded the signal strength of the serving cell by a predetermined margin.
WO 2009/131870 discloses a method for prioritizing and reporting handover events. Even though this prior art method reduces the quantity of reported events by avoiding communicating multiple redundant handover events, it remains a problem to more efficiently manage handover scenarios in rapidly changing radio environments.
This is especially true in dense urban scenarios, with high load and complex radio environment (for example in metropolitan areas with high buildings like Manhattan/Hong Kong etc), where cells may appear and disappear very fast when a mobile terminal moves around in such an environment. In order to make HO and mobility work in such complex environments, good cell planning and network parameter tuning, though important and beneficial, may not be enough to ensure mobile connectivity with low disturbances or even interruption.